Intermediates for dipyrrylmethene dyes

ABSTRACT

Novel Dipyrrylmethene dyes, particularly 5 and/or 5&#39;&#39;-odihydroxyphenyl dipyrrylmethene dyes, and 1:1 metal complexes thereof.

United States Patent Bloom et a1. 1 1 May 13, 1975 1 1 INTERMEDIATES FOR(51] Int. Cl. C07d 27/26 DIPYRRYLMETHENE [W125 [581 Field of Search.260/326.5 M. 326.3. 326.5 J, [75] Inventors: Stanley M. Bloom. Waban;Paulina 260/31 P. Garcia, Arimgton. both ofMass 56] Reference cited [73]Assignee: 5:22:01! Corporation. Cambridge, UNn-ED STATES PATENTS3.285.931 11/1966 Huiagen 260/3131 [22] Filed: May 5, i972 PrimaryExaminer-Joseph A. Narcavage [2t] Appl' Attorney, Agent. or Firm-John P.Morley Related U.S. Application Data [62] Division 01 Ser. No. 723.474.April 23. 1968. [57] ABSTRACT Novel Dipyrryimethene dyes, particularly 5and/or 0 5-o-dihydroxypheny1 dipyrryimethene dyes. and 1:1 [52] US. Cl.260/3265 J, 260/240.1, 260/2407, metal complex thereof 260/3765 M;260/3131, 260/3263, 260/295 AM; 260/296 R; 96/92; 96/93 4 Claims, 1Drawing Figure INTERMEDIATES FOR DI PYRRYLMETH ENE DYES CROSS REFERENEETO RELATED APPLICATIONS This application is a division of U.S. Pat.Application Ser. No. 723,474 filed April 23, 1968, now U.Sv Pat. No.3,691,161.

BACKGROUND OF THE INVENTION 3 .3 .5 ,5 '-tetraphenyldipyrrylmethene llIL and a copper complex containing two dye molecules to one copper atomhas been disclosed in the Journal of the Chemical Society, 1943, page596,

Metal-complexed dyes such as the aforementioned 2:1 complex generallyexhibit markedly greater stability against the color degradation effectsof actinic radiation, humidity and/or heat than do the non-complexeddyes. However, in certain applications 1:1 complexes are markedlysuperior to 2:1 complexes For example, 1:1 complexes exhibit sharperspectral absorption curves with lesser absorption in unwanted regions ofthe spectrum and hence are of greater value in subtractive colorphotographic systems directed to providing accurate color reproductionsof the subject matter. Moreover, in any uses involving diffusion ortransfer of the dye from one element to another, eg, in diffusiontransfer color photographic systems wherein an imagewise distribution ofdye is transferred to a dyeable straturn to impart thereto a dye image,the relative mobility of the dye is important and may in fact becritical to practical use of the dye. Obviously, a 2:1 complex(containing two molecules of dye) is considerably more bulky and henceless mobile than a 1:1 complex.

The present invention is, therefore, directed to novel dipyrrylmethenedyes which may be employed to obtain 1:1 metal complexes, unlike thepreviously disclosed tetraphenyldipyrrylmethene, and to 1:1 metalcomplexes obtained therefrom. Simply stated, the present invention isdirected to novel analogues of the previously disclosed3,3'-5,5'-tetraphenyldipyrrylmethene, which analogues will provide 1:]complexes as distinguished from the previously disclosed dye which willonly provide 2:] complexes.

SUMMARY OF THE INVENTION The novel dyes of this invention may be definedas being dipyrrylmethenes containing an o-hydroxyphenyl radical, i.e.,o-hydroxyphenyl or an o-hydroxyphenyl radical containing substituentsbonded to other nuclear carbon atoms, in at least one of the 5 and 5'positions. The novel metal-complexed dyes of this invention are 111metal complexes of the above-mentioned dyes. The complexes may furtherinclude any ligand, preferably a non-chromophoric ligand, if necessaryto satisfy the coordination number of the particular metal employed toform the complex, as is common to the art of forming dye complexesgenerally.

BRIEF DESCRIPTION OF DRAWING The FIGURE is a graphic illustrationcomparing the spectrophotometric curve of a typical magenta dye of thisinvention with two other magenta dyes.

DESCRIPTION OF PREFERRED EMBODIMENT In the preferred embodiment, thenovel 1:1 metal complexes are complexes of a transition metal, e.g., Cr,Mn, Fe, Co, Ni, Cu, Ru, Rd, Pd, Pt, Ag, Ir, Au, etcl, although metalsother than the transition metals, e.g., Cd, Zn, Mg, etc. are alsocontemplated.

As was mentioned previously, this invention relates to noveldipyrrylmethene dyes and to 1:1 metal complexes of such dyes.

A primary object of this invention, therefore, is to prepare novelnon-complexed dyes of the foregoing description.

Another object is to prepare novel 1:1 metall complexes of such dyes.

Still another object is to provide novel intermediates for use inpreparing the novel dyes of this invention.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps and the relationand order of one or more of such steps with respect to each of theothers, and the product possessing the features, properties and therelation of elements which are exemplified in the following detaileddisclosure, and the scope of the application of which will be indicatedin the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawing.

The novel dipyrrylmethene dyes of this invention containing a 5 and/or5'-o-hydroxyphenyl radical may be represented structurally by thefollowing formula:

wherein: each R, which may be the same or different,

may be alkyl of l-l 8 carbon atoms, preferably 16 carbon atoms, aryl,e.g., phenyl or naphthyl, substituted aryl, eg. a phenyl or naphthylnucleus containing one or more of the following substituents: hydroxy,chloro, methyl, ethyl, methoxy, ethoxy, COOH, CONH- etc,

may be an alkyl of 1-6 carbon atoms, preferably less than four carbonatoms, i.e., methyl, ethyl, propyl, or isopropyl, andN,N-dimethylaminoalkyl, N,N- diethylaminoalkyl or N-methyl,N-ethylaminoalkyl wherein the alkyl moiety contains l-6 carbon atoms,preferably less than 4 carbon atoms,

each Z, which may be the same or different, may be hydroxy, chloro,alkoxy, preferably lower alkoxy containing i,e., l6 carbon atoms, e g.,methoxy, ethoxy, etc.; alkyl, preferably lower alkyl containing 1-6carbon atoms, e.g., methyl, etc, carboxy or amido;

m is a positive integer from 1-4, it being understood that where m is l,each of the carbon atoms of the benzene nucleus is unsubstituted, i.e.,contains a hydrogen atom; and

X is hydrogen or hydroxy, provided that where Q does not comprise anohydroxyphenyl or substituted o-hydroxyphenyl, as heretofore described,X must be hydroxy.

The preferred dyes of formula A are those within the following formula:

wherein each R, which may be the same or different, is methyl, ethyl,phenyl or a substituted phenyl of the formula:

O is methyl, ethyl, phenyl, o-dihydroxyphenyl, and methyl and/0rmethoxy-substituted phenyl, includ ing those having an o-hydroxysubstituent;

each Z is hydroxy, methyl or methoxy;

m is a positive integer from 1 to 3;

and X has the meaning heretofore noted, provided again that where 0'does not provide an odihydroxyphenyl moiety, X must he hydroxy.

As examples of illustrative dyes contemplated by this invention, mentionmay be made of the following:

l H N [0 0H N on I H N H 3O l I L H CH3 I on I It will be noted thatcompounds l4 and 15 are dye developers, that is dyes which are alsosilver halide developing agents, the developing function in thisinstance being supplied by the p-dihydroxyphenyl moiety. in addition tobeing capable of being complexed to provide a lzl metal complex, thedyes of compounds 14 and l are thus of separate utility in thephotographic systems for preparing color images described and claimed inU.S. Pat. No. 2,983,606 issued to Howard G. Rogers. In such systems, aphotosensitive element comprising one or more light-sensitive silverhalide emulsions each having a dye developer associated therewith isexposed and then contacted with an aqueous alkaline processingcomposition to develop the photosensitive element and as a function ofdevelopment to provide an imagewise distribution of diffusible dye whichis transferred, at least in part, by diffusion, to a superposed dyeablestratum to impart thereto a dye transfer image.

It will be appreciated, however, that if the dye is first complexed, thedeveloping function is effectively removed so that a metal complex of adye of formulae l4 and 15 may not be employed as a dye developer in suchsystems.

The dyes of formulae l6 and 17 are also dye developers. However, it willbe observed that the developing function is contained on a differentportion of the molecule so that a metal complex of these dyes may beemployed as a dye developer in the foregoing patented system. The metalcomplex may be formed prior to color image formation, in which case itis employed in the manner described in the aforementioned patent and inU.S. Pat. No. 3,218,164 issuedto Milton Green, et al., or it may becomplexed after color image formation to increase the stability againstfading of the thus formed color print. In like manner, noncomplexed dyedevelopers such as those of formulae l4 and l5 may be employed toprovide color transfer images which can be complexed after imageformation. The aftercomplexing of dye transfer images is described, forexample, in U.S. Pat. Nos. 3,08l,167 and 3,196,0l4.

The novel dyes of this invention may be made by condensing a pyrrole ofthe formula:

with a 5-formylpyrrole of the formula:

w) R R R l l l m-MQ i c O or by condensing a pyrrole of the formula:

(E) R R i l o c l l B Q with a pyrrole of the formula:

(Fl R R W (ml) X H to obtain the desired compound of formula A.

The pyrroles of formula C may in turn be prepared by reacting a compoundof the formula:

I l Q C C CH R with nitromethane to form a compound of the formula:

(H) O R Q C C CH R l e N0 followed by hydrogenation in the presence of asuitable hydrogenation catalyst, e.g., Raney nickel, to effectreduction, ring-closure, and dehydrogenation to form the desiredcompound of formula C. However, where 0 comprises a hydroxyphenylsubstituent, the starting compound of formula G preferably employs theprotected methoxy analogue, in which event the correspondingmethoxyphenyl pyrrole is formed. To obtain the desired hydroxyphenylcompound, Le, a pyrrole of formula C wherein 0 comprises a hydroxyphenylsubstituent, the methoxyphenyl analogue is then demethylated by knowndemethylation techniques, e.g., by reaction with boron tribromide.

The compounds of formula F may be obtained by the same procedure, namelyby reacting a vinyl ketone of the formula:

CH-R

(in-l) followed by hydrogenation, ring closure and dehydrogenation inthe manner described above. Again, where X is intended to be hydroxy,the methoxy analogue is first prepared. followed by demethylation asdescribed above.

The Slormyl compounds of formula D may be prepared by reaction ofacompound of Formula F with dimethylformamide and POCI In like manner theformyl compounds of formula E may be prepared by the same reaction of acompound of Formula C.

1n the aforementioned reactions, potassium cyanide may be employed inlieu of nitromethane, if desired.

Where the compounds of formula A are symmetrical, i.e., where bothpyrrole moieties contain the same substituents, they may be prepared byreacting a compound of formula C or a compound of formula F with formicacid or a derivative:

RCHO

to form the desired compound of formula A. They may also be prepared byreacting a compound of formula C with HC(OC H or an aromatic carboxylicacid, e.g., benzoic acid.

The compounds of formula C and E wherein Q is odihydroxyphenyl or asubstituted o-dihydroxyphenyl and the compounds of formulae D and Fwherein X is hydroxy are themselves novel compounds, as are the methoxyanalogues thereof as noted above.

Metal complexes of the novel dyes of this invention may be prepared inthe manner common to the art of dye complexing, namely reacting the dyewith a metal salt, e.g., an organic salt. This may be accomplished, forexample, by refluxing a solution of the reactants for the requisitetime. The resulting complex may be readily recovered from the reactionmixture by conventional techniques, e.g., filtration. Where necessary tosatisfy the coordination number of the metal employed, a ligandproviding the requisite number of coordinating atoms, i.e., auni-dentate or multi-dentate ligand, will be required to form the 1:]complex, as will be appreciated. Useful ligands may be selected fromthose heretofore employed for such purposes, e.g., pyridine, diethylenetriamine, etc. Useful ligands are described, for example, in InstabilityConstants of Complex Compounds, Yatsimirskii and Vasilev, Pergamon PressInc,

The particular reaction conditions in the foregoing reactions will bereadily apparent to those skilled in the art and per see comprise nopart of the present inven tion.

The following examples show by way of illustration and not by way oflimitation the preparation of the novel dyes and dye complexes of thisinvention.

EXAMPLE l To a well-stirred solution of 33.6 g. (0.84 mole) of sodiumhydroxide in 30?. g. of water and 154 g. ofethano] was added 100 g.(0.66 mole) of 2- methoxyacetophenone under a nitrogen atmosphere at C.Seventy-five grams (0.66 mole) of bcnzaldchyde was added to the mixture,after which it was stirred at room temperature for 12 hours in an inertatmosphere.

a l c ca R At the end of such time, the mixture was extracted with three200-ml. portions of ether. The combined ether extracts were washed withtwo -ml. portions of water, dried over anhydrous magnesium sulfate, andconcentrated by flash evaporation. Subsequent distillation of theresidual liquid in vacuo afforded 108.3 g. (68.8%) of 2-methoxychalcone, b.p. l446 C/0.04 mm. (mp. 38-9 C) (Found: C, 81.29", H, 6.14,C H O requires C, 80.60; H, 5.98) To a mixture of 108.3 g. (0.45 mole)of 2-methoxychalcone (prepared as above) and 30.8 g. (0.42 mole) ofnitromethane in 566 ml. of anhydrous methanol was added a methanolicsolution of sodium methoxide, prepared from 11.5 g. of sodium and 142ml. of anhydrous methanol, over a period of 40 minutes under a nitrogenatmosphere at a temperature of about 38 C. The mixture was stirred atroom temperature for the next 2 hours, after which it was neutralizedwith glacial acetic acaid and then chilled overnight. The off-whitesolid was removed by suction filtration and recrystallized once fromethanol. There was obtained 90.5 g. (66.2%) of 'y-nitro-B-phenyl-Z-methoxybutyrophenone, m.p. 9l2 C. (Found: C, 68.20; H, 5.87; N,4.81 C H NO requires C, 68.30; H, 5.70; N, 4.68.) grams (0.47 mole) of7-nitro-l3-phenyl-Z-methoxybutyrophenone (prepared as above) and Raneynickel, in 500 ml. of ethyl acetate was allowed to absorb hydrogen in aParr shaker at room temperature until the theoretical uptake had beenreached. The catalyst was removed by filtration and washed with smallportions of ethyl acetate. The solvent was removed by flash evaporationand the residual oil was completely dehydrated on a steam cone atreduced pressure overnight. The resulting brown oil and 50 g. of 30percent palladium or carbon was refluxed with 1.5 l. of p-cymene for 24hours. The catalyst was removed by filtration and washed with smallportions of p-cymene. The combined filtrate and washings wasconcentrated to 200 ml. during which time the crude product separated.One recrystallization of this crude product from ligroine, b.p. 90] 20C., afforded 47 g. (40% of 2-o-anisyl-4-phenylpyrrole, m.p. l056 C.(Found: C, 8.05; H, 5.96, N, 5.66. C H NO requires C. 81,861 H, 6.08; N,5.63.) U.V. i\,,,,,," 241 (622,800) A 316 (615,200). To a solution of47.0 g. {0.l9 mole) of 2-o'anisyl-4-phenylpyrrole in 450 ml. ofanhydrous methylene chloride was added 148 g. (0.59 mole) of borontribromide with stirring over a period of l hour. Stirring at roomtemperature was continued for an additional 6 hours. At the end of thistime, 90 ml. of methanol and 216 ml. of 10 percent hydrochloric acid wasadded dropwise in succession to the reaction mixture. The methylenechloride layer was separated, washed thoroughly with water, and thendried over anhydrous magnesium sulfate. The solvent was removed by flashevaporation and the residue was purified by boiling its methanolicsolution with Norit A. Subsequent removal of methanol by slowevaporation and extraction of the residue with boiling ligroine, b.p.90120C., gave 21.0 g. (47%) of Z-o-hydroxyphenyl- 4phenylpyrrole, m.p.127.5-l29 C. (Found: C, 82.12; H, 6.20; N, 5.80. C H NO requires C.81.60; H, 5.68; N, 5.96. uv. x ,,,"""""*242 my. (622,000

mwm 27 y 4 AMHIMMWH 31 (618,200). A mixture of 5.0 g. (21.0 mM) of 2-0-hydroxypheny1-4-phenylpyrrole and 5.0 g. (20.0mM) of2,4-diphenyl--formy1pyrro1e in 300 ml. of anhydrous methanol was treatedwith short bursts of dry hydrogen chloride at about 25 C. until nofurther precipitation of the green solid was observed. The reactionmixture was stirred for an additional 3 hours and then chilled. Thecrude dye mixture was removed by suction filtration, washed with smallportions of cold methanol. and then ether. There was obtained 10.0 g. ofcrude dye, m.p. 211-2l4 C. Ten grams of the dye mixture in 1.3 l. ofmethylene chloride was treated with 50 ml. of triethylamine. Theresulting solution was chromatographed on 4.8 X 40 cm. column ofWoelmneutral a1umina. Continuous elution of the column with methylenechloride gave the first fraction, which yielded 1.30 g. (13.8%) of3,3',5,5-tetraphenyldipyrrylmethene, m.p. 284286 C. Mixed melting pointwith an authentic sample showed no appreciable depression. Thechromatogram was extruded and then extracted with methanol-methylenechloride (1:20) until most of the dye base had been removed. The extractwas evaporated to dryness in vacuo. Two recrystallizations of theresidue from nitrobenzene afforded 6.0 g. (68%) of 3,-3.5-tripheny1-5-o-hydroxyphenyldipyrrylmethene, the compound of formula1, m.p. 260-1 C. )t,,,,,,"""" 542 mu; e=44,000 C=1.8 X M (Found: C,85.75; H, 5.12; N, 6.16; O, 3.45 C H N O requires C, 85.40; H, 5.20; N,6.03; O, 3.45.) An abbreviation for methyl cellosolve, i.e.,B-methoxyethanol] EXAMPLE 2 3,3-Dipheny1-5,5'-di-(o-hydroxyphenyl)dipyrrulmethene ([11). A mixture of5.0 g. (21.0 mM) of 2-0- hydroxyphenyl-4-phenylpyrrole, 40 ml. of formicacid (97%-l00%), and 10 ml. of hydrochloric acid (sp. gr. 1.19) wasrefluxed for 12 hours, after which it was chilled. The crude product wasremovd by suction filtration, washed with ether, and then boiled with200 m1. of methanol containing 5 m1. of triethylamine for 15 minutes.The crude dye base, which separated on cooling, was recrystallized twicefrom pyridinemethanol (1:4). There was obtained 4.5 g. (88%) of 3,-3'-dipheny1-5,5-di-(ohydroxypheny1) dipyrrylmethene, the dye of formula2, mp. 268-9 C. )t 556; e=47,800 C=1.8 X l0 M (Found: C, 82.85; H, 5.07;N, 5.71; O, 6.62. C H N O requires C, 82.50, H, 5.04; N, 5.83; O, 6.66.)

EXAMPLE 3 To a well-stirred solution of 100 g. (0.67 mole) of 2-methoxyacetophenone and 40 g. (0.91 mole) of acetaldehyde in 200 ml. ofanhydrous methanol was added 64 ml. of methanolic sodium methoxide,prepared from 3.2 g. of sodium metal and 64 m1. of anhydrous metha n01,at about 10 Cover a period of 1 hour. After addition was complete, themixture was stirred at 510 C. for the next hours. At the end of thistime, glacial acetic acid was added dropwise until the solution wasneutral. The solvent was removed by distillation and the residual liquidwas diluted with 250 ml. of water and then extracted with three 150-m1.portions of ether. The combined ether extracts were dried over anhydrousmagnesium sulfate and concentrated on a flash evaporator until thesolvent had been removed. Subsequent distillation of the residual oil invacuo gave 27.6 g. of a pale yellow oil, b.p. 138140 C/mrn. Assay byvapor phase chromatography showed the oil contained 42.2% of3-(o-anisyl)-propene 2 and 47.0% of B-methoxy-o-methoxybutyrophenone.Twenty-seven grams of the foregoing mixture and 0.3 g. of freshly fused,finely pulverized zinc chloride were heated at an oil bath temperatureof l50l60 C. and an internal pressure of mm. until all the methanol hadbeen eliminated. The residual mixture was cooled to room temperature,acidified with 50 ml. of 3% acetic acid. and then extracted with two100-ml. portions of ether. The combined ether extracts were washed withwater, dried over anhydrous magnesium sulfate, and concentrated on aflash evaporator. Subsequent distillation of the residual oil in vacuogave 10.3 g. of 3-(oanisyl)-propene 2, b.p. 879 C./0.05 mm. Assay byvapor phase chromatography showed the distillate was 96% pure. To awell-stirred mixture of 5.3 g. (0.03 mole) of 3-(oanisyl)-propene-2(prepared as above and 1.8 g. (0.03 mole) of glacial acetic acid in 40m1. of ethanol was added 3.9 g. (0.06 mole) of potassium cyanide in 10ml. of water over a period of 10 minutes at 3540 C. After addition wascomplete, the reaction mixture was stirred at this same temperature foran additional 3 hours. The mixture was chilled and the crude product wasremoved by suction filtration and washed with water. Onerecrystallization from ethanol gave 3.0 g. (49.3%) ofB-cyano-omethoxybutyrophenone, m.p. 63-4 C. Found: C, 70.85; H, 6.40; N,6.96; O, 15.81. C H N0 requires C, 70.90; H, 6.45; N, 6.90; O. 15.80. 47grams (0.23 mole) of B-cyano-omethoxybutyrophenone and Raney nickel in200 ml. of ethyl acetate was allowed to absorb hydrogen in a Parr shakerat room temperature until the theoretical hydrogen uptake had beenreached. The catalyst was removed by filtration and washed with smallportions of ethyl acetate. The solvent was removed by flash evaporationand the residual oil was completely dehydrated on a steam cone atreduced pressure overnight. There was obtained 35.0 g. of an isomericmixture of crude pyrroline. The foregoing mixture (35.0 g.) and 8.0 g.of 30% palladium on carbon in 200 ml. of pcymene was refluxed for 2hours under a nitrogen atmosphere, after which the catalyst was removedby filtration and washed with small portions of p-cymene. The solventwas removed by flash distillation and the residual liquid was distilledin vacuo. There was obtained 13.7 g. (31.8%) of2-o-anisoy1-4-methylpyrr0le, b.p. 7 C./0.05 mm. Found: C, 76.85; H,6.83; N, 7.43; O, 8.36. C H NO requies C, 76.95; H, 7.00; N, 7.48; O,8.55. UV x fl 289 mu (613,000); A 310 mp. (14,000). To a well-stirredsolution of 14.0 g. (0.075 mole) of 2-o-anixoy1-4-methy1pyrrole in m1.of dry methylene chloride was added 45.2 g. (0.18 mole) of borontribromide over a period of 40 minutes. After addition was complete themixture was stirred at room temperature for 6 hours. At the end of thistime, 50 ml. of methanol and 100 m1. of 10 percent hydrochloric acid wasadded in succession. The reaction mixture was stirred at roomtemperature for 1 hour, after which it was extracted with four 75-m1.portions of methylene chloride. The combined extracts were washedthoroughly with water, dried over anhydrous magnesium sulfate, andevaporated to dryness in a flash evaporator. Subsequentrecrystallization from ligroine {b.p. 90l20 C.) and decolorization withNorit gave 3.3 g. (25.4%) of 2-o-hydroxypheny1-4methylpyrro1e, m.p. 834C. Found: C, 76.25; H, 6.34; N. 8.05; O, 9.45. C H NO requires C, 76.25;H, 6.43; N, 8.08; O,

9.25 UV A,,,,, 285 mp. (61 ,200) )t,,,,, 315 mp. (12,600). A mixture of2.6 g. (15.0 mM) of 2-ohydroxyphenyl-4methyl-pyrrole and 1.85 g. (I5.0mM) of 2,4dimethyl-S-formylpyrrole in 60 ml. of anhydrous methanol wastreated with short bursts of am hydrous hydrogen chloride at about 25-30C. until no further precipitation was observed. Subsequent chilling gavethe crude dye, which was removed by suction filtration and washed withcold methanol, basified with triethylamine, boiled on a steam bath for10 minutes and then chilled. One recrystallization of the resulting dyebase from methanol-triethylamine gave 3.0 g. (72%) ofo-hydroxyphenyl-3',3,5-trimethyldipyrrylmethene, the compound of formula3, m.p. 1245 C. A (MeCell) 490 mu, F 42,800; Elemental Analysis: Cale.C, 77.60; H, 6.54; N, 10.08; O, 5.75; Found: C, 77.1 1', H, 6.73; N,9.65; O. 5.63.

EXAMPLE 4 A mixture of 0.5 g. (2.9 mM) of 2ohydroxyphenyl-4-methylpyrrole, 5.0 ml. of formic acid (99100%) and drops ofhydrochloric acid (sp. gr. 1.19) was refluxed for 1.5 hours, after whichit was cooled and stirred with 35 ml. of ether. The precipitate was removed by suction filtration. washed thoroughly with ether andrecrystallized once from methanoltriethylamine. There was obtained 030g. (75.0%) of 3,3"dimethyI-S,5'-di-o-hydroxypheny1- dipyrrylmethene, thecompound of formula 4, m.p. 2245 C. k (MeCell) 536 mu; e= 48,300;Elemental Analysis: Calc. C, 77.60; H, 5.68; N, 7.87; O, 8.95; Found: C,77.68; H, 5.76; N, 7.67; 0, 8,86.

EXAMPLE 5 A mixture of 4.7 g. (20.0 mM) of 2-o-hydroxyphenyl4-phenylpyrrole and 2.46 g, (20.0 mM) of 2,4-dimethyl-5-formylpyrro1e in70 ml. of anhydrous methanol was treated with short bursts of anhydroushydrogen chloride at about 30 C. until no further precipitation wasobserved. Subsequent chilling gave the crude dye, which was removed bysuction filtration and washed with cold methanol. This crude dye wassuspended in 70 ml. of methanol, basified with triethylamine, boiled ona steam bath for 10 minutes and then chilled. On recrystallization ofthe resulting dye base from methanol-triethylamine gave 60 g. (88.5%) of5'- o-hydroxyphenyl-3 -phenyl-3,S-dimethyldipyrrylmethene, the compoundof formula 5, m.p. l67-9 C. A (MeCell) 495 mu; F 42,800; Elemental Analyses: Cale. C, 81.10, H, 5.94; N, 8.24; O, 4.71; Found: C, 80.40; H,6.09; N, 8.35; O, 4.98.

EXAMPLE 6 A mixture of 0.50 g., (1.0 mM) of3,3',5,5'tetraphenyldipyrrylmethene and 0.30 g. 1.4 mM of zinc acetatedihydrate was refluxed with 25 ml. of n-butanol for one hour, afterwhich it was chilled. The precipitate was removed by suction filtration,washed with small portions of methanol, and recrystallized once frompyridine-methanol There was obtained 0.50 g. (93%) of the 2:1 zinccomplex of 3,3',5,5'-tetraphenyldipyrrylmethene m.p. 2934 C. 1\,,,,,,""529 mu; e 110,000 (=18 X 10 M (Found: C, 82.70; H, 4.84; N, 5.96; Zn,6.77 C H N ln requires C, 82.52; H, 4.83; N, 5.83; Zn. 6.81.)

EXAMPLE 7 A mixture of 0.51 g., (1.] mM) of 5'-ohydroxyphenyl-3,3,5-triphcnyl-dipyrrylmethene, 0.35

g, (2.2 mM J, of zinc acetate dihydrate, and 0.67 g. oi tricthylaminewas refluxed with ml. of absolute ethanol for 2 hours, after which itwas poured into ml. of cold water with stirring. The residue was removed by suction filtration, washed thoroughly with water, and dried invacuo over Drierite at 60 C. Purifi cation was accomplished byextracting this resiude with absolute ethanol in a Soxhlet extractor for48 hours. There was obtained 0.41 g. (66%) of the zinc complex of 3,3,5-triphenyl5-o-hydroxyphenyldipyrrylmethene, m.p. 300 C. A 593 mu; e74,000 C 18 X 10 M (Found: C, 70.65; H, 4.68; N, 4.83; Zn, 12.93. C H ,NO Zn H O requires C, 70.24; H, 4.66; N, 4.97; Zn, 11.60.)

EXAMPLE 8 A mixture of 0.48 g. (1 mM) of 5,5-bis(ohydroxyphenyl)-3,3'-diphenyldipyrrylmethcne, 0.24 g. (1.1 mM) of zincacetate dihydrate, and 0.5 g. (5.0 mM) of triethylamine was refluxedwith 50 ml. of absolute ethanol for 1 hour, after which it was pouredinto 100 ml. of cold water with stirring. The residue was removed bysuction filtration, washed thoroughly with water, and dried in vacuoover Drierite at 60 C. Purification was accomplished by extracting thisresidue with absolute ethanol in a Soxhlet extractor for 24 hours. Therewas obtained 0.36 g. (62.4%) of the zinc complex of3,3'-diphenyl-5,5-his(o-hydroxyphenyl)dipyr rylmethene, m.p. 300 C. A613; 575 mp, e 60,000; 24,000 C=1.8 X 10 M (Found: C, 67.57; H, 5.63; N,4.75; Zn, 10.97. C H N O- Zn (H O) H O requires C, 68.30; H, 4.55; N,4.83; Zn, 11.25.)

EXAMPLE 9 A mixture of 0.48 g. (1 mM) of 5,5'-bis(ohydroxyphenyl)-3,3'-diphenyldipyrromethene, 0.25 g. (1 mM 10% excess)of cobalt acetate tetrahydrate, and 1.0 g. (12.7 mM) of pyridine in 50ml. of absolute ethanol was refluxed for 1 hour, after which it wascooled and diluted with 150 ml. of water. The green precipitate wasremoved by suction filtration, washed thoroughly with water, dired invacuo at 60 C. over Drierite, and then extracted with absolute ethanol.One recrystallization of the ethanol insoluble material from pyridineethanol (1:4) afforded 0.40 g. (58%) of the cobalt complex of5,5'-bis(ohydroxyphenyl)-3,3'- diphenyldipyrrylmethene, m.p. 300 C.Anal. Calcd. for C H ,N,,O Co: C, 74.30; H, 4.52; N, 8.07; Co, 8.48;Found: C, 74.21; H, 4.76; N, 8.03; Co, 8.55; )t,,,,,,""" 665 mu, e25,500.

EXAMPLE 10 The copper complex of 5,5'-bis(o-hydroxyphenyl)3,3'-diphenylpyrrylmethene was prepared by substituting copper acetatefor the cobalt acetate in Example 6. Yield: 15.6%; m.p. 300 C. Anal.Calcd. for [C H N O CWHU 0.2C H OH: C, 70.30; H, 5.40; N 4.43;Cu, 10.02;Found: C, 71.06; H, 4.24; N, 4.80; Cu, 9.74; )t,,,,,,'"""' 651 mue37,500.

EXAMPLE 11 The nickel complex of 5,5'-bis(o-hydroxyphenyly3,3-cliphenyldipyrrylmethene was prepared in the same manner. Yield:32.2%; m.p. 300 C, Anal. Calcd, for lC H- N O Ni" H O*] 0.2H O: C,66.90; H, 4.09, N, 5.73; Ni, 9.94; Found: C, 66.85; H, 4.10; N, 5.20;Ni, 9.94; )t 680 mu; e d 23,300.

EXAMPLE 12 A mixture of 0.5l g. l .1 mM of o-hydroxypher yl-3,3',5'-triphcnyldipyrrylmcthene and 0.5 g. (2.0 mM) of nickel acetatetctrahydrate in 50 ml. of dimethylformamide was refluxed for l hour,after which it was cooled and diluted with 150 ml. of ice water. Theprecipitate was removed by suction filtration, washed thoroughly withwater, and dried in vacuo over Drierite at 60 C One purification bydissolution in dimethylform' amide and and reprecipitation with waterafforded 0.56 g. (94.5%) of the nickel complex ofhydroxyphenyl3,3,5-triphenyldipyrrylmethene, :np. 300 C. Anal. Calcd.for C H N O Ni; C, 72.70; H, 4.94, N, 7.07; Ni, 9.90; Found: C, 73.01;H, 4.84, N,

6.86; Ni, 9.82, h 544 (emax 16,200); 6l3 (l9,000);7l8(l3.200).

EXAMPLE l3 A mixture of 0.42 g. (1.5 mM) of5'-ohydroxyphenyl-3,3,53,5-trimethyldipyrrylmethene, 0.33 g. (1.5 mM 10%excess) of copper acetate monohydrate, and 0.35 g. of pyridine in 50 ml.of ethanol was refluxed for 30 minutes, after which it was poured into100 ml. of ice water. The crude complex was removed by suctionfiltration and washed thoroughly with water. One recrystallization frompyridineethanol gave 0.39 g. (62.3%) of the copper complex of5'-ohydroxyphenyl-3,3,5-trimethyldipyrrylmethene, mp. 249--250" C.

EXAMPLE 14 In a similar manner, using pyridine as ligand, the coppercomplex of 5'-o-hydroxypheuyl3'-phenyl-3,5- dimethylpyrrylmethane wasprepared in 54% yield, m.p. 300 C., A (MeCell) 559 mu; 5 53,900.

EXAMPLE l5 Using p-benzylpyridine as ligand, the nickel complex ofo-hydroxyphenyl-3'-phenyl-3,5-dimethylpyrrylme thene was prepared in44.8% yield. m.p. 278280 C., a (MeCell) 548 my; F 54,500,

EXAMPLE 16 Using p benzylpyridine as ligand, the zinc complex of theabove dye (formula 5) was prepared in 75.6 yield, mp. 288289.5 C., u(MeCell) 550 mu; 6 39,400; may. 6 39,400.

EXAMPLE l7 Using pyridine as ligand, the cobalt complex of the above dyewas obtained, mp. 286290 G, m"! (Me- Cell) 540 mu, 6 l7,8t)0.

Elemental analyses of all ofthe metal complexes prepared in theillustrative examples confirmed that they were all lzl complexes. exceptfor the prior art 2:] complex prepared in Example 6.

The novel dyes of this invention are fugitive, not being stable to lightin their non-complexed form for any appreciable period of time. However,the metal complexes of these dyes are of good light and chemicalstability. The transition metal complexes are appreciably more stablethan the non-transition metal com plexes and hence are preferred.

The spectral absorption curves of these dyes show that they as a classpossess sharp peaks and narrow bands. Stated another way, these dyesprovide maximum absorption over a narrow region of the visible spectrumand minimal absorption elsewhere over regions of the spectrum which inpractical use would be regarded as unwanted absorption.

Other known dyes, e.g., the cyanine dyes, possess similar spectralabsorption characteristics, but are also characteristically bothfugitive and incapable of existing in a form possessing adequatestability. Hence, the present dyes are markedly superior in that theyare both stable in complexed form and possess brilliant spectralabsorption characteristics.

The spectral absorption curves of: (1) an illustrative dye of thisinvention, the copper-pyridine complex of the dye of formula 3; (2) astandard control magenta dye,2-[p-(2',5'-dihydroxyphenethyl)-phenylazo]-4- iscpropoxy-l-naphthol',and (3) a chromiumcomplexed dye, lnochrome Pink N, have been superposedin the graph of the drawing to illustrate the supe' rior spectralabsorption characteristics of the dyes of this invention overrepresentative useful dyes heretofore employed in the art, the numeralson the drawing corresponding to those recited above. Note the sharp peakand narrow band of the claimed dyes.

The spectral absorption curves were obtained by swabbing a solution ofthe dye onto a dyeable stratum such as would be employed in preparing aphotographic dye image. Reflectance curves were then run with standardapparatus for this purpose.

The ratio of the maximum absorption (D at the peak of the curve to theminimum absorption (D,,,,,,) at a fixed point. 450 mg was calculated foreach of the dyes. a conventional means of analyzing and comparing thebrilliance and quality of magenta dyes. The band width midway betweenthe D and D,,,,-,, (half-band width) of the dyes were also calculatedfurther to com pare the brilliance and sharp peaks of the dyes. Thisdata is set forth below:

mu: Half-Band Width 'Rlll 1. Formula 3 7.3 SIX to 584 66 2. ControlMagenta 3.1 460 to 595 max Half-Band Width 3- lnochromc Pink N 3.3 473[o 590: 117

The stability of each of the three dyes to the degradative effects oflight was evaluated in conventional manner by subjecting the respectivestrata containing them to tests under 21 Xenon are at 128 F. and 31%relative humidity. After eight hours the dye of formula 3 had only faded8% while the control magenta had faded 39%, as calculated by comparingthe D at the beginning of the test to the D,,,,, after 8 hours. Thechromium complex. lnochrome Pink N exhibited greater stability, but asnoted above, did not possess as good a spectral absorption curve.

By way of recapitulation, dyes are known which have greater stabilitythan the claimed metal complexes. Dyes are also known, e.g., the cyaninedyes, which possess a bril iance and spectral absorption characteristicscomparable to the claimed dyes. The remarkable thing about the claimeddyes is thus not each individual trait alone, but the combination ofboth. Typically, the nar row band, sharp peak brilliant dyes arefugitive or unstable and are not capable ofexisting in a form possessingstability adequate for most purposes, eg, by complexing; whereas dyes ofsufficient stability for the con templated use, rig, in colorphotography, do not pos sess as fine spectral absorption curves.

The essence of the present invention, therefore, is providing a novelclass of dyes which combine both of these qualities and qualifications.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawing shall be interpreted as illustrative and not ina limiting sense.

What is claimed is:

l. A pyrrole of the formula:

where: one R is hydrogen and the other is a substituent chosen from thegroup consisting of methyl, ethyl, phenyl each Z is hydroxy, methyl ormethoxy and m is a positive integer from 1-3. 2. A pyrrole of theformula:

i l Z (m-l) N on l or (m l) each Z is hydroxy, methyl or methoxy and mis a positive integer l to 3. 3. A pyrrole of the formula:

where: one R is hydrogen while the other is a suhstituent chosen fromthe group consisting of methyl, ethyl, phenyl each Z is hydroxy, methylor methoxy and m is a positive integer from l to 3. 4. A pyrrole of theformula Z (tnwhere: one R is hydrogen and the other is a substituentchosen from the group consisting of methyl, ethyl, ph enyl each Z ishydroxy, methyl or methoxy and m is a positive integer from l to 3.

1. A pyrrole of the formula:
 2. A PYRROLE OF THE FORMULA:
 3. A PYRROLEOF THE FORMULA: 2-(2,5-DI(HO-)PHENYL),3,4-DI(R-),5-(H-CO-)PYRROLE WHERE:ONE R IS HYDROGEN WHILE THE OTHER IS A SUBSTITUENT CHOSEN FROM THE CROUPCONSISTING OF METHYL, ETHYL, PHENYL
 4. A pyrrole of the formula